1. Field of the Invention
This invention relates, generally, to anti-theft devices. More particularly, it relates to a device that prevents theft of diesel fuel from diesel fuel dispensers.
2. Description of the Prior Art
A thief can steal diesel fuel from a diesel fuel dispenser by using a crowbar or other suitable implement to pry back a cover of the dispenser a short distance and to insert the same implement, or another implement, into the hollow interior of the dispenser to disable a pulser. The function of the pulser is to generate electrical signals that report the amount of fuel consumed to the electronics of the dispenser so that the quantity and price of dispensed fuel may be displayed to the consumer.
The liquid control meter of the dispenser continues to operate when the pulser is disabled and diesel fuel is delivered to the consumer. However, the fluid flow is not detected by the disabled pulser. An attendant monitoring a computer screen that receives information from the pulser will be unaware that fuel is being dispensed.
Since theft is so easy when a pulser is unprotected, the station attendant is unaware that a theft has occurred until an honest trucker reports that a dispenser is dispensing free fuel. By then, several of the initial thief's friends and others willing to take advantage of the broken dispenser may have filled their respective saddle tanks.
Most gasoline theft is committed by people who fill their car's tank and drive off without paying, secure in the knowledge that law enforcement authorities have little time available to search for and apprehend such thieves. Since such theft is relatively uncommon, and since the amount of fuel stolen per incident is considered to be a nominal amount by the industry, not much attention has been paid to ways to stop such theft.
However, large trucks are equipped with gas tanks known as saddle tanks that can hold two to three hundred gallons of diesel fuel. Drive off theft of diesel fuel is rare because trucks accelerate slowly and a station owner has plenty of time to write down a license plate number. Due to the large scale of such a theft, law enforcement authorities will search for and apprehend such thieves.
Thieves have therefore designed new ways to get free diesel fuel. The most widely spread technique is to pry back a cover of the diesel fuel dispenser, commonly known as a fuel pump, and disable the pulser. A pulser counts the revolutions of a liquid control meter and includes a coupler that interconnects the dispenser's liquid control meter and the pulser. When the liquid control meter and the pulser are decoupled from one another, fuel continues to flow but no electrical signal indicating such flow is generated, and a thief may drive off without attracting attention because no sale will have registered on the dispenser or on the remote monitor that is watched by an attendant. Accordingly, after prying back the cover of a diesel fuel dispenser, the thief uses a suitable tool to poke the coupler. The coupler is not designed to withstand such an attack and it is relatively easy to knock out of its functional position. With the coupler knocked out of place, the liquid control meter is no longer coupled to the pulser and fuel is dispensed without detection.
Several attempts have been made in an effort to stop this type of theft. A large metal band is sometimes wrapped around the dispenser in an effort to prevent prying away of the cover. The bands quickly stretch and loosen, however, enabling thieves to pry back the cover without any problem. Some thieves simply cut off such bands if they are encountered.
Another attempt includes the impaling of the dispenser with a large bolt that extends from the front cover to the rear cover. Although this makes complete removal of the covers difficult, it does little to prevent a thief from prying back a corner of the cover to expose the internal workings of the dispenser. The amount of prying required is nominal a pencil width crack is all that is needed to expose the pulser and its vulnerable coupler.
The manufacturers of dispensers could solve the problem by re-designing the dispensers, but such re-designing would require a huge investment. Nor is it obvious as to what form such re-designing would take, i.e., inventive effort would be required in such re-designing. Redesigning and replacing the thousands of diesel fuel pumps in use throughout the world is simply not a cost-effective option.
A more suitable solution would be a low cost device that could be retrofit onto existing dispensers.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how such a device could be provided.